128 Proceedings of the Royal Physical Society. 
the site of the old Borough Loch—were laid open by a series 
of deep drains, the sections of which exhibited in the “lower 
and earlier deposits a fine silt separated into lamine as thin 
as pasteboard,” crowded with impressions of the common 
water flag and reed, then above the silt “‘a bed of grey marl 
composed mainly of lacustrine shells with an occasional 
land shell.” Over this marl occurred in some parts three feet 
of peat-moss, having still preserved in it the “ glossy elytra of 
beetles in their prismatic tints of azure and green.” The silt 
is considered to be a rain wash of clay and soil from the 
ground surrounding the old lake. The marl is referred to as 
the “dead exuview of generation after generation of fresh- 
water Mollusca for many ages, which at length filled up the 
depths of the lakes till there was no place for the living; then 
water mosses sprang up in the marly shallows, and gradually 
contracted its area, until what had been open water became 
unsightly morass, and the old Borough Loch was transformed 
into the Meadows.” Mr Miller records two species of Cyclas, 
three species of Limnea, but makes no mention of Ostracoda, 
probably because in 1842 their significance as indicative of 
lacustrine conditions was not recognised. | 
The lake marls we have examined are ten in number, and 
were gathered within the last twenty years from the various 
exposures which occurred during that time; not, it should be 
mentioned, with the view of being described and their 
organisms enumerated. as in this paper, but partly as employ- 
ment for leisure hours, and partly at the imstance of Mr 
David Robertson, who was engaged in the study of the 
recent freshwater Ostracoda, and who made some use of the 
material collected. It was only within the last few months 
that the idea of making this use of the surplus material 
occurred to us as preliminary to a more exhaustive study of 
the freshwater Crustacea of the Edinburgh district which 
one of us (T. Scott) intends to make. Six of the marls or 
silts were obtained from within or immediately around 
Edinburgh; three—those of Corstorphine, Hailes, and Redhall 
—about four miles west of it; and one—that of Kethymyre— 
about six miles to the north across the Forth, and is included 
because it conforms, in the conditions and circumstances of 
